Apparatus for removal of gases from liquids



April 15, 1952 c. H. GOODWIN 2,592,680

7 APPARATUS FOR REMOVAL OF GASES FROM LIQUIDS Filed May 14, 1946 INVENTOR.

CHESTER H. GOODW/A/ Patented Apr. 15, 1952 APPARATUS FOR REMOVAL 'OF GASES FROM LIQUIDS Chester H. Goodwin, Nitro, W. Va... assignor to American Viscose Corporation, Wilmington, DeL, a corporation of Delaware Application May 14, 1946, Serial No. 669,670

Claims.

The present invention relates to a method and apparatus for removing bubbles of air or other gases from liquids, such as from viscose solutions, from simple liquids, mixtures of liquids, solutions of liquids within liquids or of solids and/or gases within liquids. The invention particularly is concerned with the utilization of centrifugal force for accomplishing such bubble-removal.

In general, the present invention provides for supplying the bubble-charged liquid into a centrifuge having an outwardly and upwardly sloped wall which allows the liquid to flow continuously upwardly and to be continuously displaced by fresh liquid entering near the bottom. The liquid as it becomes increasingly more bubble-free or more deaerated in its upward passage finally overflows the upper outer rim of the wall and flows into an annular collecting channel surrounding the upper zone of the centrifuge. The flow of the liquid from the upper rim of the centrifuge wall into the annular channel is controlled to make it as smooth as possible, avoiding substantially all tendency toward turbulence which would reduce the efficacy of the operation. The efliciency of the procedure is greatly increased by the provision of a generally centrally located discharge eonduit within the centrifuge for removing the portion of the liquid which is lighter either by virtue of entrainment of gas bubbles or by dispersion or dissolution of gas within the liquid. Other objects and advantages of the invention will be apparent from the drawing and the description thereof hereinafter.

In the drawing which is illustrative of the form of equipment which may be used to carry out the invention,

Figure 1 is a cross-section of an elevation of one embodiment, and

Figure 2 is a section taken on line II-II of Figure 1.

As shown, the centrifuge bowl 2 has an upwardly'and outwardly sloped wall 3 which terminates in an upper edge or rim provided with a downwardly inclined flange 4. For the reasons which will be explained more particularly hereinafter, the inclination of the wall 3 from the vertical is preferably less than so that the total angle or divergence between the opposite walls of the bowl is less than 30. The bowl 2 is rotatably mounted upon a stationary base 5 which may be provided as shown more particularly in Figure 2, with an annular groove 6 in its bearing surface. This groove communicates with a conduit I connected to the supply tank 8 containing the liquid from which the gas or air bubbles are to be removed. The bottom of the centrifuge bowl is provided with a plurality of slots 9 adapted to register with the groove 6 in the face of the bearing plate.

A shaft I0 is keyed to the hub ll of the bowl as at I2. As shown, the hub and shaft extend through the bearing 5 and the shaft is driven by means of the pulley l3, belt l4, pulley l5 and the motor 16. The shaft It may extend through additional bearings shown at I! and [8 to provide additional support.

A cap or hood I9 is supported in a bracket or frame 20 so that it is adjustable vertically therein, such as by the screw 2|. This hood overhangs the flange or rim 4 and extends into the upper region of the annular collecting trough 22 and preferably the lower edge or lip of hood I9 is immersed in the collected liquid contained in trough 22. A manifold 23 connected to the trough 22 by short lateral branch conduits 24 is connected to the suction side of the pump 25 from which the deaerated liquid may be forced through the discharge conduit 26 for any disposition, such as to a storage vessel or a spinning machine.

As shown, the inside surface of the hood [9 which faces the outside annular surface of the flange 4 is concentrically related thereto and is spaced a small distance therefrom, such distance being varied depending upon the particular liquid handled, its viscosity characteristics, and the rate of flow through the centrifuge. This distance should never be so large that the liquid flowing over the flange 4 does not make contact with the hood I9.

Preferably, the shaft I0 is hollow to serve as a discharge conduit for the lighter portion of the liquid which may still contain an accumulation of gaseous bubbles. The upper end of the hollow shaft l0 may serve as the sole means of entry of the liquid into the shaft but preferably, as shown, ports 21 may be provided in the upper region of the shaft. Such ports may merely comprise cylindrical bores extending radially through the shaft wall. However, it is preferred that the ports 21 extend through the wall at an angle as shown in Figure 2 and that they be slit-like, with the length of the slit extending axially of the shaft, as shown in Figure 1. Such of the liquid as flows by gravity through the shaft I0 is received in a container 28 from which it may be transferred by pump 29 into the vessel 8 for return to the centrifuge. The clearance between the rotating shaft 10 and the cover of container 28 allows venting of gases from the system. The tank 8 may be continuously supplied with additional liquid through a conduit 30.

Although the equipment shown and described in Figures 1 and 2 may be utilized for the handling of any bubble-charged liquid, its operation will be described as applied to the deaeration of viscose for which it is highly advantageous. The bowl 2 is rotated at a high speed which may be varied as desired from about 300 to 10,000 R. P. M. depending. upon the viscosity of the liquidsupply. As the liquid flows upwardly along the inside of the outer wall 3 it progressively becomes deaerated and flows over the outer upper edge of" the wall 3 into the space between. the rim. land the cap [9.

As the body of viscose flows upwardly along the inside of the wall of the centrifuge, the outer portion of the liquid is subjected to a compression resulting from the reaction of centripetal force against centrifugal force. This compres-' sion effect increases as the liquid moves upwardly in the centrifuge bowl and thereby acquires a greater radius from the axis of rotation and as the liquid. rises there is progressively stronger tendency toward deaeration.

. The space between the rim 4 and thecap l9- maybe adjusted depending upon the speed of operation of thedevice, the viscosity of the medium, etc., to obtain the smoothest possible flow, so that the liquid from which the gas has-been removed iscaused to flow" downwardly into the liquid'contained in the discharge trough 22 without .any appreciable turbulence.-

If the liquid as originally supplied to the centrifuge contains a large proportion of air bubbles, or is of a highly viscous nature, such asis often the case with viscose solutionsused for spinning filaments or forming films. of regenerated cellulose, a certain proportion of the liquid will. tend to become surcharged with the gas bubbles'as it flows upwardly in the centrifuge andsuch portion will move inwardly by virtue of its .lighter density so that. it will flow through.

the shaft 10 intothe vessel28. Rotation is preferably in the." direction of the arrow shown in Figure 2, sothat the inclination of the ports 21 tends to produce a skimming action within the body of liquid which tends to lag behind the speed of the centrifuge itself.

In the vessel 28, such surcharged material is in a relative state of, rest or slow movement, so.

that a considerable amount of the air bubbles can break free at the exposed surface before the liquidis withdrawnby the pump 29.

This function of the hollow shaft [0' applies to, the handling of other liquids besides viscose solutions, such as solutions of cellulose derivatives-of, which cellulose acetate. in acetone isrepresentative, resin solutions or dispersions, and

the like. Of course, there may beliquids whichdo: not tend toretain the bubbles when surcharged by; the action of the centrifuge and in such cases the hollow shaft will generally not discharge any of the liquid. For handling such solutions, the ports 21 may be entirely absentor the speed of the centrifuge mayrbe increased suf ficiently; to prevent any contact of the liquid wit theapertured' portion of the shaft I0. V g

It is to'be understoodthat changes and variations maybe made without departing from-the" and downwardly therefrom, means extending through the bottom of the bowl for introducing a liquid into the bowl, means disposed around the bowl for collecting the liquid discharged from the overflow flange, a stationary hood having an outwardly and downwardly extending surface spaced a small distancefrom, and; arranged concentrically with the flange; said surface of the hood extending into the collecting means, a hollow drive shaft extending through the bottom of the, bowl toa generallycentrally located region above the bottom of the bowl, said shaft being apertured near. its upper end to provide communication. between its bore and said centrally located region.

2. centrifuging apparatus comprising a bowl having a-Wall whose circumference as a result of a wall divergence of less than about 30 increases in an upward direction, an overflow flange at the upper end of the bowl extending outwardly and downwardly therefrom, means extendingthrough the bottom of" thebowl for introducing'a liquid into the bowl; means disposed: around the bowl for collecting the liquid discharged from theoverflow flange, a stationary hood having an outwardly and downwardly extending surface.

'cumference increases in an upward direction to ajmaximum atthe upper endof the bowl, an Qverflowflangeatthe upper end of the bowl extending outwardly and downwardly therefrom, means extendingthrough the bottom of the bowl for introducing a liquid'into the bowl; a hollow drive I shaft for. rotating the bowl, extending through the'bottomoflthe bowl and having aperturesatfits' upperend' within the bowl, means disposed .aroundthebowl for collecting the liquid discharged from, the. overflow flange, and; a stationary hood having an outwardly, and-downwardly. extendingsurface spaced a smalldistance from; and. arranged,concentrically with, the, flange, saidsurface of. the. hood extending. into thecollectingmeans; V

4. centrifuging..apparatuscomprising ,a bowl.

4 having a wall'whose internal circumference in;

creases in.an upward directionto a maximum at the upper end of the bowl; an.overfl'o.w fiangeat. the-upper end of the-bowl extending outwardly and downwardly therefrom, means for introducinga ,liquidintothe bowl, means disposed around thebowlior collecting, the liquid discharged-from. the: overflow flange,,a,.s.tationary hood having.

an. outwardly. anddownwardlwextending. surface spaced .a small distance from, and arranged concentrically. with,.the flange, saidsurface'of. the hood extending-into the collecting means, a.

drive, shaft. andmeans comprising a. conduit extending through the driveshaftandhaving apere tures. at its upper .endydisposed in the bowl for.

removinganyliquid present in a generally-cen.--

trally located region of the bowl.

. 5i -Centrifuging-,apparatus.- comprising a bowl. havingga 1 wall whose internal circumference as a.

resultaoftar wall. divergence of. less than about: 30.? increasesin; an. upward directiontoa maximum;

at the upper end of the bowl, an overflow flange at the upper end of the bowl extending outwardly and downwardly therefrom, means extending through the bottom of the bowl for introducing a liquid into the bowl, means disposed around the bowl for collecting the liquid discharged from the overflow flange, a stationary hood having an outwardly and downwardly extending surface spaced a small distance from, and arranged concentrically with, the flange, said surface of the hood extending into the collecting means, a drive shaft, a conduit extending through the drive shaft and the bottom of the bowl in a generally centrally located region above the bottom of the bowl, said conduit being apertured near its upper end to provide communication between its bore and said centrally located region.

CHESTER H. GOODWIN.

REFERENCES CITED The following references are of record in the file of this patent:

Number UNITED STATES PATENTS Name Date Saint-Denis Dec. 5, 1893 Holmes June 17, 1902 Land May 5, 1903 Coombs May 14, 1912 Gue Jan. 5, 1915 Weston et a1 Mar. 23, 1915 Tolman Nov. 16, 1920 Wineman Jan. 2, 1923 Walch 1 Nov. 5, 1935 Stiger Nov. 26, 1940 FOREIGN PATENTS Country Date France Apr. 28, 1930 Great Britain Apr, 28, 1932 

